diff --git a/days/17.go b/days/17.go
new file mode 100644
index 0000000..5c37472
--- /dev/null
+++ b/days/17.go
@@ -0,0 +1,422 @@
+package days
+
+import (
+	"fmt"
+	"strings"
+
+	u "parnic.com/aoc2019/utilities"
+)
+
+type camViewCellType int
+type botFacing int
+type day17Grid [][]camViewCellType
+
+const (
+	cellTypeScaffold camViewCellType = iota
+	cellTypeOpen
+	cellTypeInvalid
+)
+
+const (
+	botFacingUp botFacing = iota
+	botFacingLeft
+	botFacingDown
+	botFacingRight
+
+	botFacingFirst = botFacingUp
+	botFacingLast  = botFacingRight
+)
+
+const (
+	dirLeft                 = 1
+	dirRight                = -1
+	maxInstructionSetLength = 20
+)
+
+var (
+	day17AdjacentOffsets = []u.Vec2i{
+		{X: -1, Y: 0},
+		{X: 1, Y: 0},
+		{X: 0, Y: -1},
+		{X: 0, Y: 1},
+	}
+)
+
+type Day17 struct {
+	program u.IntcodeProgram
+}
+
+func (d *Day17) Parse() {
+	d.program = u.LoadIntcodeProgram("17p")
+}
+
+func (d Day17) Num() int {
+	return 17
+}
+
+func (currentDir botFacing) getNewFacingDir(turnDir int) botFacing {
+	currentDir += botFacing(turnDir)
+	if currentDir < botFacingFirst {
+		currentDir = botFacingLast
+	} else if currentDir > botFacingLast {
+		currentDir = botFacingFirst
+	}
+
+	return currentDir
+}
+
+func (grid day17Grid) Draw(botLocation u.Vec2i, botFacingDir botFacing, endLocation u.Vec2i) {
+	for y := range grid {
+		for x := range grid[y] {
+			switch grid[y][x] {
+			case cellTypeOpen:
+				fmt.Print(" ")
+			case cellTypeScaffold:
+				char := "█"
+				color := u.ColorBlack
+				if botLocation.X == x && botLocation.Y == y {
+					switch botFacingDir {
+					case botFacingUp:
+						char = "^"
+					case botFacingLeft:
+						char = "<"
+					case botFacingDown:
+						char = "v"
+					case botFacingRight:
+						char = ">"
+					}
+				} else if endLocation.X == x && endLocation.Y == y {
+					char = "@"
+				} else {
+					color = u.ColorWhite
+				}
+				fmt.Printf("%s%s%s%s", u.BackgroundWhite, color, char, u.TextReset)
+			}
+		}
+		fmt.Println()
+	}
+}
+
+func (grid day17Grid) getAdjacentScaffolds(y, x int) []u.Vec2i {
+	retval := make([]u.Vec2i, 0)
+	for _, offset := range day17AdjacentOffsets {
+		offY := y + offset.Y
+		offX := x + offset.X
+		if offY < 0 || offY >= len(grid) ||
+			offX < 0 || offX >= len(grid[0]) {
+			continue
+		}
+
+		if grid[offY][offX] == cellTypeScaffold {
+			retval = append(retval, u.Vec2i{X: offX, Y: offY})
+		}
+	}
+
+	return retval
+}
+
+func (grid day17Grid) forEachCellOfType(t camViewCellType, f func(y, x int)) {
+	for y := range grid {
+		for x := range grid[y] {
+			if grid[y][x] == t {
+				f(y, x)
+			}
+		}
+	}
+}
+
+func (grid *day17Grid) processGridUpdate(y int, rVal rune, currBotLocation u.Vec2i, currBotFacing botFacing) (int, u.Vec2i, botFacing) {
+	grid.appendValue(rVal, y)
+
+	switch rVal {
+	case '\n':
+		y++
+	case '^', '<', 'v', '>':
+		currBotLocation = u.Vec2i{X: len((*grid)[y]) - 1, Y: y}
+		switch rVal {
+		case '^':
+			currBotFacing = botFacingUp
+		case '<':
+			currBotFacing = botFacingLeft
+		case 'v':
+			currBotFacing = botFacingDown
+		case '>':
+			currBotFacing = botFacingRight
+		}
+	}
+
+	return y, currBotLocation, currBotFacing
+}
+
+func (grid day17Grid) getCellTypeInDirection(y, x int, facingDir botFacing) (camViewCellType, int, int) {
+	newX := x
+	newY := y
+	switch facingDir {
+	case botFacingUp:
+		newY--
+	case botFacingLeft:
+		newX--
+	case botFacingDown:
+		newY++
+	case botFacingRight:
+		newX++
+	}
+
+	if newY < 0 || newY >= len(grid) || newX < 0 || newX >= len(grid[0]) {
+		return cellTypeInvalid, newY, newX
+	}
+
+	return grid[newY][newX], newY, newX
+}
+
+func (grid *day17Grid) appendValue(rVal rune, row int) {
+	ensureCapacity := func(y int) {
+		for len(*grid) <= y {
+			*grid = append(*grid, make([]camViewCellType, 0))
+		}
+	}
+
+	switch rVal {
+	case '#':
+		ensureCapacity(row)
+		(*grid)[row] = append((*grid)[row], cellTypeScaffold)
+	case '.':
+		ensureCapacity(row)
+		(*grid)[row] = append((*grid)[row], cellTypeOpen)
+	case '^', '<', 'v', '>':
+		ensureCapacity(row)
+		(*grid)[row] = append((*grid)[row], cellTypeScaffold)
+	}
+}
+
+func (grid day17Grid) findEndLocation(botLocation u.Vec2i) u.Vec2i {
+	var endLocation u.Vec2i
+	grid.forEachCellOfType(cellTypeScaffold, func(y, x int) {
+		if numSurrounding := len(grid.getAdjacentScaffolds(y, x)); numSurrounding == 1 {
+			if botLocation.X != x || botLocation.Y != y {
+				endLocation = u.Vec2i{X: x, Y: y}
+			}
+		}
+	})
+
+	return endLocation
+}
+
+func (grid day17Grid) getTurnDirectionFromCorner(pos u.Vec2i, botFacingDir botFacing) (int, string) {
+	adj := grid.getAdjacentScaffolds(pos.Y, pos.X)
+	turnDirection := 0
+	// this is so awful. i'm sure there's a better way, but i'm tired.
+	if botFacingDir == botFacingUp || botFacingDir == botFacingDown {
+		if u.ArrayContains(adj, u.Vec2i{X: pos.X - 1, Y: pos.Y}) {
+			if botFacingDir == botFacingUp {
+				turnDirection = dirLeft
+			} else if botFacingDir == botFacingDown {
+				turnDirection = dirRight
+			}
+		} else if u.ArrayContains(adj, u.Vec2i{X: pos.X + 1, Y: pos.Y}) {
+			if botFacingDir == botFacingUp {
+				turnDirection = dirRight
+			} else if botFacingDir == botFacingDown {
+				turnDirection = dirLeft
+			}
+		}
+	} else {
+		if u.ArrayContains(adj, u.Vec2i{X: pos.X, Y: pos.Y - 1}) {
+			if botFacingDir == botFacingLeft {
+				turnDirection = dirRight
+			} else if botFacingDir == botFacingRight {
+				turnDirection = dirLeft
+			}
+		} else if u.ArrayContains(adj, u.Vec2i{X: pos.X, Y: pos.Y + 1}) {
+			if botFacingDir == botFacingLeft {
+				turnDirection = dirLeft
+			} else if botFacingDir == botFacingRight {
+				turnDirection = dirRight
+			}
+		}
+	}
+
+	dirAscii := "L"
+	if turnDirection == dirRight {
+		dirAscii = "R"
+	}
+
+	return turnDirection, dirAscii
+}
+
+func buildInstructionString(instructions []string) string {
+	workingInstructions := make([]string, len(instructions))
+	copy(workingInstructions, instructions)
+
+	minimumRecurrence := 3
+	initialInstructionSubsetLen := 4
+
+	instructionStr := strings.Join(workingInstructions, ",")
+	progs := make([][]string, 3)
+	for i := range progs {
+		numFound := minimumRecurrence
+		subLen := initialInstructionSubsetLen
+		for numFound >= minimumRecurrence {
+			numFound = 1
+			instructionSubset := strings.Join(workingInstructions[0:subLen], ",")
+			if len(instructionSubset) > maxInstructionSetLength {
+				break
+			}
+			for x := len(instructionSubset); x <= len(instructionStr)-len(instructionSubset); x++ {
+				if instructionStr[x:x+len(instructionSubset)] == instructionSubset {
+					numFound++
+					x += len(instructionSubset)
+				}
+			}
+			if numFound >= minimumRecurrence {
+				subLen += 2
+			}
+		}
+		if numFound < minimumRecurrence {
+			subLen -= 2
+		}
+		progs[i] = make([]string, subLen)
+		copy(progs[i], workingInstructions[0:subLen])
+
+		instructionStr = strings.ReplaceAll(instructionStr, strings.Join(progs[i], ","), "")
+		instructionStr = strings.TrimPrefix(strings.ReplaceAll(instructionStr, ",,", ","), ",")
+
+		if len(instructionStr) == 0 {
+			workingInstructions = nil
+		} else {
+			workingInstructions = strings.Split(instructionStr, ",")
+		}
+	}
+
+	if workingInstructions != nil {
+		panic("failed to use up all instructions")
+	}
+
+	programStr := strings.Join(instructions, ",")
+	for i := range progs {
+		programStr = strings.ReplaceAll(programStr, strings.Join(progs[i], ","), fmt.Sprintf("%c", 'A'+i))
+	}
+
+	sb := strings.Builder{}
+	sb.WriteString(programStr)
+	sb.WriteRune('\n')
+
+	for i := range progs {
+		sb.WriteString(strings.Join(progs[i], ","))
+		sb.WriteRune('\n')
+	}
+
+	runDebug := 'n'
+	sb.WriteRune(runDebug)
+	sb.WriteRune('\n')
+
+	return sb.String()
+}
+
+func (grid day17Grid) solvePath(botLocation u.Vec2i, botFacingDir botFacing) string {
+	instructions := make([]string, 0)
+
+	pos := botLocation
+	endLocation := grid.findEndLocation(botLocation)
+	for {
+		if pos == endLocation {
+			break
+		}
+
+		turnDirection, dirAscii := grid.getTurnDirectionFromCorner(pos, botFacingDir)
+		if turnDirection == 0 {
+			panic("at an invalid location somehow")
+		}
+
+		instructions = append(instructions, dirAscii)
+
+		botFacingDir = botFacingDir.getNewFacingDir(turnDirection)
+		numMoved := 0
+		for {
+			cell, newY, newX := grid.getCellTypeInDirection(pos.Y, pos.X, botFacingDir)
+			if cell != cellTypeScaffold {
+				break
+			}
+			pos.X = newX
+			pos.Y = newY
+			numMoved++
+		}
+		instructions = append(instructions, fmt.Sprintf("%d", numMoved))
+	}
+
+	return buildInstructionString(instructions)
+}
+
+func (d *Day17) Part1() string {
+	grid := day17Grid{}
+	y := 0
+	var botLocation u.Vec2i
+	var botFacingDir botFacing
+
+	d.program.RunIn(func(inputStep int) int64 {
+		return 0
+	}, func(val int64, state u.IntcodeProgramState) {
+		rVal := rune(val)
+		y, botLocation, botFacingDir = grid.processGridUpdate(y, rVal, botLocation, botFacingDir)
+	})
+
+	alignmentParameterTotal := 0
+	grid.forEachCellOfType(cellTypeScaffold, func(y, x int) {
+		if numSurrounding := len(grid.getAdjacentScaffolds(y, x)); numSurrounding == 4 {
+			alignmentParameterTotal += y * x
+		}
+	})
+
+	// endLocation := grid.findEndLocation(botLocation)
+	// grid.Draw(botLocation, botFacingDir, endLocation)
+
+	return fmt.Sprintf("Alignment parameter sum: %s%d%s", u.TextBold, alignmentParameterTotal, u.TextReset)
+}
+
+func (d *Day17) Part2() string {
+	beforeGrid := day17Grid{}
+	var beforeBotLocation u.Vec2i
+	var beforeBotFacing botFacing
+
+	afterGrid := day17Grid{}
+	var afterBotLocation u.Vec2i
+	var afterBotFacing botFacing
+
+	d.program.Reset()
+	d.program.SetMemory(0, 2)
+
+	row := 0
+	var outputState int
+	var lastOutput int64
+	var instructionStr string
+	d.program.RunIn(func(inputStep int) int64 {
+		return int64(instructionStr[inputStep-1])
+	}, func(val int64, state u.IntcodeProgramState) {
+		rVal := rune(val)
+		if outputState == 0 {
+			row, beforeBotLocation, beforeBotFacing = beforeGrid.processGridUpdate(row, rVal, beforeBotLocation, beforeBotFacing)
+		} else if outputState == 2 {
+			row, afterBotLocation, afterBotFacing = afterGrid.processGridUpdate(row, rVal, afterBotLocation, afterBotFacing)
+		}
+
+		if rVal == '\n' && lastOutput == '\n' {
+			if outputState == 0 {
+				instructionStr = beforeGrid.solvePath(beforeBotLocation, beforeBotFacing)
+			}
+			outputState++
+			row = 0
+		}
+
+		lastOutput = val
+	})
+
+	// fmt.Println("initial grid:")
+	// beforeEndLocation := beforeGrid.findEndLocation(beforeBotLocation)
+	// beforeGrid.Draw(beforeBotLocation, beforeBotFacing, beforeEndLocation)
+
+	// fmt.Println("completed grid:")
+	// afterEndLocation := afterGrid.findEndLocation(afterBotLocation)
+	// afterGrid.Draw(afterBotLocation, afterBotFacing, afterEndLocation)
+
+	return fmt.Sprintf("Dust collected after traveling all paths: %s%d%s", u.TextBold, lastOutput, u.TextReset)
+}
diff --git a/inputs/17p.txt b/inputs/17p.txt
new file mode 100644
index 0000000..efe6ef3
--- /dev/null
+++ b/inputs/17p.txt
@@ -0,0 +1 @@
+1,330,331,332,109,2734,1102,1182,1,15,1102,1,1429,24,1002,0,1,570,1006,570,36,1001,571,0,0,1001,570,-1,570,1001,24,1,24,1106,0,18,1008,571,0,571,1001,15,1,15,1008,15,1429,570,1006,570,14,21102,58,1,0,1105,1,786,1006,332,62,99,21101,0,333,1,21102,73,1,0,1105,1,579,1101,0,0,572,1101,0,0,573,3,574,101,1,573,573,1007,574,65,570,1005,570,151,107,67,574,570,1005,570,151,1001,574,-64,574,1002,574,-1,574,1001,572,1,572,1007,572,11,570,1006,570,165,101,1182,572,127,1001,574,0,0,3,574,101,1,573,573,1008,574,10,570,1005,570,189,1008,574,44,570,1006,570,158,1105,1,81,21102,1,340,1,1105,1,177,21101,0,477,1,1106,0,177,21101,0,514,1,21101,0,176,0,1106,0,579,99,21102,1,184,0,1106,0,579,4,574,104,10,99,1007,573,22,570,1006,570,165,1001,572,0,1182,21102,1,375,1,21101,211,0,0,1106,0,579,21101,1182,11,1,21102,1,222,0,1105,1,979,21102,1,388,1,21102,233,1,0,1105,1,579,21101,1182,22,1,21101,0,244,0,1106,0,979,21101,401,0,1,21101,0,255,0,1105,1,579,21101,1182,33,1,21102,266,1,0,1106,0,979,21102,1,414,1,21102,1,277,0,1106,0,579,3,575,1008,575,89,570,1008,575,121,575,1,575,570,575,3,574,1008,574,10,570,1006,570,291,104,10,21102,1182,1,1,21101,313,0,0,1106,0,622,1005,575,327,1102,1,1,575,21102,327,1,0,1105,1,786,4,438,99,0,1,1,6,77,97,105,110,58,10,33,10,69,120,112,101,99,116,101,100,32,102,117,110,99,116,105,111,110,32,110,97,109,101,32,98,117,116,32,103,111,116,58,32,0,12,70,117,110,99,116,105,111,110,32,65,58,10,12,70,117,110,99,116,105,111,110,32,66,58,10,12,70,117,110,99,116,105,111,110,32,67,58,10,23,67,111,110,116,105,110,117,111,117,115,32,118,105,100,101,111,32,102,101,101,100,63,10,0,37,10,69,120,112,101,99,116,101,100,32,82,44,32,76,44,32,111,114,32,100,105,115,116,97,110,99,101,32,98,117,116,32,103,111,116,58,32,36,10,69,120,112,101,99,116,101,100,32,99,111,109,109,97,32,111,114,32,110,101,119,108,105,110,101,32,98,117,116,32,103,111,116,58,32,43,10,68,101,102,105,110,105,116,105,111,110,115,32,109,97,121,32,98,101,32,97,116,32,109,111,115,116,32,50,48,32,99,104,97,114,97,99,116,101,114,115,33,10,94,62,118,60,0,1,0,-1,-1,0,1,0,0,0,0,0,0,1,6,0,0,109,4,1202,-3,1,587,20101,0,0,-1,22101,1,-3,-3,21101,0,0,-2,2208,-2,-1,570,1005,570,617,2201,-3,-2,609,4,0,21201,-2,1,-2,1105,1,597,109,-4,2106,0,0,109,5,2102,1,-4,630,20102,1,0,-2,22101,1,-4,-4,21102,0,1,-3,2208,-3,-2,570,1005,570,781,2201,-4,-3,652,21002,0,1,-1,1208,-1,-4,570,1005,570,709,1208,-1,-5,570,1005,570,734,1207,-1,0,570,1005,570,759,1206,-1,774,1001,578,562,684,1,0,576,576,1001,578,566,692,1,0,577,577,21101,0,702,0,1105,1,786,21201,-1,-1,-1,1106,0,676,1001,578,1,578,1008,578,4,570,1006,570,724,1001,578,-4,578,21101,0,731,0,1106,0,786,1105,1,774,1001,578,-1,578,1008,578,-1,570,1006,570,749,1001,578,4,578,21101,0,756,0,1106,0,786,1106,0,774,21202,-1,-11,1,22101,1182,1,1,21102,774,1,0,1105,1,622,21201,-3,1,-3,1105,1,640,109,-5,2106,0,0,109,7,1005,575,802,21002,576,1,-6,20101,0,577,-5,1105,1,814,21102,1,0,-1,21102,1,0,-5,21102,0,1,-6,20208,-6,576,-2,208,-5,577,570,22002,570,-2,-2,21202,-5,29,-3,22201,-6,-3,-3,22101,1429,-3,-3,1202,-3,1,843,1005,0,863,21202,-2,42,-4,22101,46,-4,-4,1206,-2,924,21102,1,1,-1,1105,1,924,1205,-2,873,21102,1,35,-4,1105,1,924,1202,-3,1,878,1008,0,1,570,1006,570,916,1001,374,1,374,2101,0,-3,895,1101,2,0,0,2102,1,-3,902,1001,438,0,438,2202,-6,-5,570,1,570,374,570,1,570,438,438,1001,578,558,922,20101,0,0,-4,1006,575,959,204,-4,22101,1,-6,-6,1208,-6,29,570,1006,570,814,104,10,22101,1,-5,-5,1208,-5,45,570,1006,570,810,104,10,1206,-1,974,99,1206,-1,974,1101,1,0,575,21101,973,0,0,1105,1,786,99,109,-7,2105,1,0,109,6,21101,0,0,-4,21102,1,0,-3,203,-2,22101,1,-3,-3,21208,-2,82,-1,1205,-1,1030,21208,-2,76,-1,1205,-1,1037,21207,-2,48,-1,1205,-1,1124,22107,57,-2,-1,1205,-1,1124,21201,-2,-48,-2,1105,1,1041,21102,-4,1,-2,1106,0,1041,21101,-5,0,-2,21201,-4,1,-4,21207,-4,11,-1,1206,-1,1138,2201,-5,-4,1059,1201,-2,0,0,203,-2,22101,1,-3,-3,21207,-2,48,-1,1205,-1,1107,22107,57,-2,-1,1205,-1,1107,21201,-2,-48,-2,2201,-5,-4,1090,20102,10,0,-1,22201,-2,-1,-2,2201,-5,-4,1103,2101,0,-2,0,1106,0,1060,21208,-2,10,-1,1205,-1,1162,21208,-2,44,-1,1206,-1,1131,1105,1,989,21101,439,0,1,1105,1,1150,21102,1,477,1,1105,1,1150,21102,1,514,1,21102,1,1149,0,1105,1,579,99,21101,1157,0,0,1106,0,579,204,-2,104,10,99,21207,-3,22,-1,1206,-1,1138,2101,0,-5,1176,1202,-4,1,0,109,-6,2105,1,0,6,5,28,1,28,1,28,1,28,1,28,1,20,11,1,7,10,1,7,1,1,1,1,1,5,1,10,1,5,11,1,1,10,1,5,1,1,1,1,1,1,1,3,1,1,1,10,9,1,1,1,1,1,5,16,1,3,1,1,1,1,1,1,1,18,5,1,1,1,1,1,1,24,1,1,1,1,1,24,1,1,1,1,1,24,1,1,1,1,1,24,5,7,1,18,1,9,1,18,1,9,1,18,1,9,1,18,1,9,1,18,1,9,1,12,7,9,1,12,1,15,1,12,1,15,1,12,1,15,1,12,1,15,1,12,1,15,1,2,5,5,1,9,7,2,1,3,1,5,1,9,1,8,1,3,1,5,1,9,1,8,1,3,1,5,1,9,1,8,1,3,13,3,1,8,1,9,1,5,1,3,1,8,11,5,1,1,5,22,1,1,1,1,1,1,1,22,1,1,1,1,1,1,1,22,1,1,1,1,1,1,1,22,13,18,1,1,1,1,1,5,1,16,5,1,1,5,1,16,1,1,1,3,1,5,1,16,1,1,11,16,1,5,1,22,7,6
\ No newline at end of file
diff --git a/main.go b/main.go
index 7820b04..af9ca68 100644
--- a/main.go
+++ b/main.go
@@ -47,6 +47,7 @@ var dayMap = []day{
 	&days.Day14{},
 	&days.Day15{},
 	&days.Day16{},
+	&days.Day17{},
 }
 
 func main() {
diff --git a/utilities/vector.go b/utilities/vector.go
index ad2bb0f..0a7bee1 100644
--- a/utilities/vector.go
+++ b/utilities/vector.go
@@ -13,6 +13,8 @@ type Vec3[T Number] struct {
 	Z T
 }
 
+type Vec2i Vec2[int]
+
 func (v Vec2[T]) Dot(other Vec2[T]) T {
 	return (v.X * other.X) + (v.Y * other.Y)
 }